Digital communication systems typically include a mobile unit, which may be embodied in a digital cellular telephone or any other portable communication device, and infrastructure units, which may be embodied in a cellular base stations or any other suitable communication hardware. During operation, the mobile unit and an infrastructure unit exchange digital information using one of a number of communication protocols.
A number of different digital communication schemes are known. For example, second generation code-division multiple access (CDMA) systems are disclosed in the IS-95 communication standard, which is available from the Telecommunication Industry Association (TIA). Additionally, third generation (3G) standards and systems, which are typically referred to as WCDMA (Wideband CDMA) standards and systems, are emerging. One of the most prevalent WCDMA standards that is currently being developed is the IS-2000 standard, which is an evolution of the IS-95 standard. Additionally, the Universal Mobile Telecommunications System (UMTS) standard is an emerging WCDMA standard that is an evolution of the global system for mobile communications (GSM) standard.
In general, wireless communications applications are continually increasing the rate at which data is transferred. The International Telecommunications Union (ITU), via the IS-2000 standard, has required that standards bodies specify 3G systems enabling mobile wireless data communication at 384 kilobits per second (kbps) and fixed wireless data communication at 2 megabits per second (Mbps). To achieve these data rates, CDMA mobile units and CDMA infrastructure must exchange data using multiple channels in the same frequency band. In high data rate systems, a particular mobile unit may receive multiple channels of information in the same frequency band through the use of digital codes, such as Walsh codes, that are used to encode data transmitted by the infrastructure units. For example, WCDMA infrastructure encodes two portions of data for transmission to a particular mobile unit with the PN code for that mobile unit and encodes the first portion of data with a first Walsh code and encodes the second portion of data with a second Walsh code, thereby sending two channels of data to the mobile unit. Accordingly, the receiver of the mobile unit must recover these channels of data at a high rate and must process the data associated with all Walsh codes that the receiver is to process.
The volume of data that must be processed and the high rate of processing necessitate the use of hardware accelerators. However, as will be readily appreciated, powering multiple hardware accelerators to detect multiple channels carrying data for the mobile unit is costly both in terms of mobile unit battery life and processing demands.